Single-Protein Control on Nanoarrays generated by Dip-Pen Nanolithography

D. MaspochInstitut Catala de Nanotecnologia, Spain, ES

Keywords: Dip Pen Nanolithography, DPN

Abstract:

Dip Pen Nanolithography (DPN) is a direct-write scanning probe lithography in which an AFM tip is used to deliver chemical reagents directly to nanoscopic regions of a substrate. As a direct-write technique, DPN has recently emerged as a particular attractive tool for directly patterning biological entities at the nanometer scale while preserving their biological activity. With these capabilities, DPN provides the potential not only to fabricate more and more miniaturized arrays but also to control the number of biomolecules (proteins, viruses, etc.) deposited on a desired region of a substrate. In this communication, we will describe how DPN can be used to control the number of protein entities deposited on a substrate. Ferritin protein has been chosen as an excellent model system because of its size and central inorganic core of hydrated iron (III) oxide, which allows its visualization by TEM, and therefore, its individual identification on the surface of the TEM grids. By combining the fabrication of ferritin arrays directly onto carbon films of TEM grids and the use of this characterization technique, we have studied how the number of ferritin entities deposited on each dot feature depends on two parameters: the dot diameter and the initial concentration of ferritin “ink”. From this study, and by choosing the proper values of both parameters, we are currently able to control the number of ferritin entities positioned on each spot of a nanoarray. We believe that this capability will certainly open up new avenues to the biochemical and biomedical research communities to study biomolecules individually rather than collectively.